James Webb Space Telescope discovers extreme exoplanet being roasted by its home star

If you thought summer here on Earth could get pretty brutal, spare a thought for the extrasolar planet, or exoplanet, designated HD 80606 b. Using the James Webb Space Telescope, astronomers have discovered that this gas giant exoplanet, located 217 light-years away, is being roasted by its host star.

The planet, it seems, really puts the "hot" in "Hot Jupiter," a category of gas giant planets that come so close to their stars that they can complete an orbit in a matter of days, sometimes even hours.

The 111-day orbit of HD 80606 b brings the exoplanet so close to its host star that the James Webb Space Telescope (JWST) saw its temperature soar to an incredible 1,100 degrees Fahrenheit (600 degrees Celsius). This causes an extreme change in the chemistry of this world, which makes it an ideal case study for the JWST.

"Hot Jupiters are already considered some of the most extreme exoplanets we know of, but even among that population, HD 80606 b is one of the most extreme," team leader Tiffany Kataria of NASA's Jet Propulsion Laboratory in Southern California said in a statement. "We typically think of hot Jupiters as hot gas giants sitting right next to their stars, but this planet's highly eccentric orbit creates a completely different beast."

Who ordered the roasted exoplanet?

Kataria and colleagues investigated HD 80606 b, its temperature and its chemistry using a technique in astronomy called spectroscopy, which breaks light down into individual wavelengths. This can reveal a world's chemistry because elements absorb and emit light at characteristic wavelengths.

Thus, when light from a star passes through the atmosphere of a planet, the chemicals in that atmosphere leave their fingerprints on this spectrum.
Using the JWST's MIRI (Mid-Infrared Instrument), the team observed this Hot Jupiter before, during, and after its close approach to its parent star, HD 80606. This required a great deal of planning given the extremely elliptical orbit of HD 80606 b.

This isn't the first time astronomers have studied HD 80606 b, the roasted exoplanet was previously investigated using NASA's now-defunct Spitzer Space Telescope.

"Spitzer did amazing work on this exoplanet, and now the JWST is building on that legacy by enabling us to drill down to distinguish specific chemical signatures like methane and carbon dioxide, which is just amazing progress," team member Ryan Challener of the Cornell Center for Astrophysics and Planetary Science said in the statement. "There's so much to learn from this one dataset here — we really are just getting started deciphering what the JWST has to tell us."

The JWST has followed that work to present a far more detailed picture of this exoplanet than before. In fact, the $10 billion space telescope has revealed that HD 80606 b is even more violent than anticipated.

"The JWST has shown that the planet’s increase in temperature was even more extreme than we anticipated based on Spitzer data," Kataria said.

The team's findings were presented Tuesday (June 16) at the 248th meeting of the American Astronomical Society in Pasadena, California.